I converted a Beta 1 project to Beta 2 and made a few fixes to get it up and running. However, I noticed the testpage.html was still looking for the previous version of Silverlight 2 Beta 1. It's a quick fix: Create a new Silverlight 2 Beta 2 project/solution and grab the source for the %Project%TestPage.html and use it for your existing project. All you have to change is the path to the .xap file.